The invention relates to a radial piston engine according to the pre-characterizing clause of claim 1.
A radial piston engine of this type is known from German Auslegeschrift No. 2,244,920. In order to guide the pivotal movement and stroke movement in the cylinders of the hollow pistons in contact with the eccentric, the pistons are each slidable in the axial direction in the bushing which is provided with a spherical surface on the external circumferences and is mounted in a corresponding bearing shell inserted in the cylinder. Due to design considerations, the spherical bearing bushing can only be constructed as a relatively narrow section. The incident operating pressure presses the externally spherical bearing bushing into the inner section of the bearing shell, whereby a surface pressure results between bushing and bearing shell which is several times greater than the incident operating pressure. Consequently substantial forces which result from the high surface pressure of the bearing bushing in the bearing shell have to be overcome during the operation of the engine. There are also, resulting from this, high edge forces on the pistons due to a relatively short guided length, which in turn influence the friction forces in the longitudinal movement of the piston. The efficiency of the engine is influenced substantially by these forces which have to be overcome.